Toe iron for safety ski bindings

ABSTRACT

A soleholder constitutes the coupling member of a four-bar linkage, which comprises levers pivoted to a baseplate and which is held in its normal position by a spring. The baseplate is provided with fixed abutments, which in the normal position of the toe iron are engaged by the levers at those ends thereof which do not carry the soleholder. Each abutment has a concave abutting surface, which at its mutually opposite sides adjoins a recess, which is capable after a spring-opposed movement of the soleholder to receive that lever which leads in the direction of movement so that so the soleholder can be pivotally moved to its open position without an effort.

United States Patent Marker et al.

[451 Ang. 22, 1972 [54] TOE IRON FOR SAFETY SKI BINDINGS [73] Assignee: To said Marken, said Jungkind,

part interest [22] Filed: Sept. 16, 1970 [21] Appl. No.: 72,717

[30] Foreign Application Priority Data Sept. 29, 1969 Germany ..P 19 49 123.7

[52] US. Cl. ..280/11.35 T [51] Int. Cl ..A63c 9/00 [58] Field of Search ..280/11.35 T

[56] References Cited UNITED STATES PATENTS 3,232,631 2/1966 Witschard ....280/l1.35 T 3,366,394 1/ 1968 Shimizn ..280/1 1.35 T

3,125,349 3/1964 Schneizer ..280/] 1.35 T

Primary Examiner-Benjamin Hersh Assistant ExaminerRobert R. Song Att0mey-Fleit, Gipple & Jacobson 7] ABSTRACT A soleholder constitutes the coupling member of a four-bar linkage, which comprises levers pivoted to a baseplate and which is held in its normal position by a spring. The baseplate is provided with fixed abutments, which in the normal position of the toe iron are engaged by the levers at those ends thereof which do not carry the soleholder. Each abutment has a concave abutting surface, which at its mutually opposite sides adjoins a recess, which is capable after a springopposed movement of the soleholder to receive that lever which leads in the direction of movement so that so the soleholder can be pivotally moved to its open position without an effort.

5 Clains, 6 Drawing Figures PATENTED M1622 I972 SHEET 2 [IF 3 PATENTED Am; 22 1972 saw 3 BF 3 TOE IRON FOR SAFETY SKI BINDINGS The present invention relates to a toe iron for safety ski bindings, which toe iron comprises a soleholder which constitutes the coupling member of a four-bar linkage, which comprises levers pivoted to a baseplate and which is held in its normal position by a spring.

Such toe iron is already disclosed in a prior applica tion and compared to other known four-bar linkage toe irons in which the soleholder member is locked relative to the baseplate has the important advantage of being insensitive to shock. On the other hand, it is relative complicated and involves a large structural expenditure. That expenditure is undesirable not only because it results in high manufacturing costs of the toe iron but also because it renders the toe iron more liable to be deranged.

It is an object of the invention so to improve and design a toe iron of the kind described first hereinbefore that the disadvantages of the toe iron proposed before are avoided in a simple manner.

In a toe iron for safety ski bindings, which toe iron comprises a soleholder which constitutes the coupling member of a four-bar linkage, which comprises levers pivoted to a baseplate and which is held in its normal position by a spring, the above object is accomplished according to the invention in that the baseplate is provided with fixed abutrnents, which in the normal position of the toe iron are engaged by the levers at those ends thereof which do not carry the soleholder, and that each abutment has a concave abutting surface, which at its mutually opposite sides adjoins a recess, which is capable after a spring-opposed movement of the soleholder to receive that lever which leads in the direction of movement so that the soleholder can be pivotally moved to its open position without an effort.

It has proved particularly desirable to provide each lever at its engaging end with at least one freely rotatable backing roller so that the frictional resistance of the four-bar linkage during the pivotal movement is reduced.

A structurally simple mounting of the four-bar linkage may be accomplished if the axles of the backing rollers constitute pivots of the four-bar linkage. That surface of the recess which adjoins the abutting surface constitutes suitably a guideway for the abutting end of the lever. As a result, the levers will always perform the same movements also during a pivotal movement performed without an effort and a predetermined end position of the soleholder will be ensured.

In a development of the invention, the levers of the four-bar linkage may be two-armed levers and may be so arranged that during a spring-opposed movement of the soleholder they are only rotatably held on the baseplate by means of those pivots which do not carry the soleholder. In this case, the levers are preferably provided with a slot and a pivot pin which is rigid with the baseplate extends through each of said slots and constitutes a pivot of the four-bar linkage. Alternatively, a pivot pin which constitutes a pivot of the four-bar linkage and is positively guided in a groove of the baseplate may be rigidly secured to each lever.

In a further development of the invention, the spring may be disposed between a member of the four-bar linkage which is rigid with the baseplate and at least one movable member of the four-bar linkage. Because the spring is additionally subjected to bending or buckling stresses, in such an arrangement, it has proved desirable to provide the spring between two relatively movable members of the four-bar linkage. In that case it is desirable to arrange the spring to act at one end on the soleholder and at the other hand by means of connecting levers on the levers of the four-bar linkage.

Two embodiments of the invention will now be fully described by way of example with reference to the accompanying drawings, in which FIG. 1 is a top plan view showing a first embodiment of the toe iron, partly cut open to facilitate the understanding of the mechanism.

FIG. 2 is a top plan view showing the toe iron of FIG. 1 with the soleholder in an instantaneous position immediately before the release.

FIG. 3 is a top plan view showing the toe iron according to FIG. 1 with the soleholder in its release position.

FIG. 4 is a top plan view showing a second embodiment of the toe iron also partly cut open to facilitate the understanding of the mechanism.

FIG. 5 is a top plan view showing the toe iron of FIG. 4 with the soleholder in an instantaneous position immediately before the release.

FIG. 6 is a top plan view showing the toe iron of FIG. 4 with the soleholder in its release position.

The toe iron shown in FIGS. 1 to 3 comprises a soleholder member 1, which constitutes the coupling member of a four-bar linkage and to which the soleholder proper 2 is secured with screws 3. The soleholder member 1 is pivoted by two pivot pins 4 and 5 to the levers 6 and 7 of the four-bar linkage. These levers carry freely rotatable backing rollers 8 and 9 at their other ends. The axles 10 and 11 of said rollers constitute pivots of the four-bar linkage. The four-bar linkage bears by means of the backing rollers 8, 9 on an abutment block 12, which constitutes a unit with a baseplate 13. The latter is adapted to be secured to the ski, e.g., by means of screws, and for this purpose is provided with screw holes 14.

That side of the abutment block 12 which faces the soleholder 2 has an approximately W-shaped recess. The free legs of the W are offset and are formed each with a concave abutting surface 15 or 16, which is normally engaged by the backing rollers 8, 9 of the toe iron. A closing bar 17 connected by screws 18 to the abutment block 12 closes the W-shaped recess and prevents a sliding of the backing rollers 8, 9 out of the recess. To prevent an upward movement of the fourbar mechanism at the abutment block 12, each roller has a collar 19, which extends into a groove 20, which is formed in the abutment block 12 and in the closing bar 17 and in constant depth in the peripheral surface of the recess.

A connecting lever 21 is pivoted to the pivot pin 4 which connects the soleholder member 1 to the lever arm 6. From its normal position, the connecting lever 21 can perform a pivotal movement relative to the lever 6 only in one direction. Another connecting lever 22 is mounted on the pivot pin 5 and non-rotatably held relative to the lever 7. The connecting levers 21, 22 are so arranged that their free ends overlap and in the normal position of the toe iron said free ends contact each other at a point which is disposed on the longitudinal center line of the toe iron.

A U-shaped sheet metal member 23 has a leg which is secured between the soleholder member 1 and the soleholder 2 and its other leg carries a pin 24 formed with a transverse bore. To facilitate the understanding of the mechanism, part of the web portion of the sheet metal member 23 is shown broken away in the drawings. A helical tension spring 25 is stressed between the pin 24 and the free end of the connecting lever 21. The ends of said spring are reversely bent in the shape of hooks and extend in the transverse bore of the pin 24 and in a bore of the connecting lever 21, respectively. The four-bar linkage is held in its normal position shown in FIG. 1 by that spring and can be moved out of said normal position only against spring force, as is shown, e.g., in FIG. 2.

'If the soleholder 2 is subjected to the action of a force in a direction which is transverse to the longitudinal direction of the ski, e.g., a force directed to the right in FIGS. 1-3, and said force overcomes the spring force, the levers 6, 7 will swing about the pivots land 1 1 and will move the soleholder 2 along an are having a center of curvature which at least approximately coincides with the axis of rotation of the skiing boot on the ski. As a result, the stress of the helical compression spring 25 is increased. Upon a decrease of the force exerted by the skiing boot on the soleholder 2, the spring 25 acting by means'of the connecting lever 21 pulls the lever 6 to its normal position so that the soleholder 2 and the skiing boot also return to their initial position. If a force which exceeds the force required for a release acts on the soleholder 2 not only as a shock, the four-bar linkage will initially perform the movement described hereinbefore until it reaches the position shown in FIG. 2. Upon a continued movement of the soleholder 2, the backing roller 8 will spring out of its concave abutting surface and under the action of the stressed tension spring 25 will roll along the guideway 26 formed by the corresponding leg of the W- shaped recess until the roller reaches'a stop (see FIG. 3). During that movement, the soleholder performs a pivotal movement to the position shown in FIG. 3 and suddenly releases the skiing boot. When the latter has been released, the four-bar linkage may automatically return to its normal position under the action of the tension spring 25 if the toe iron is designed accordingly. If the soleholder is subjected to the action of a force which is transverse to the longitudinal direction of the ski and directed to the left in FIGS. 1-3, the connecting lever 22 exerts pressure on the connecting lever 21 so that the latter performs a pivotal movement relative to the lever 6 and stresses the helical tension spring 25. In other respects, the toe iron has the same function as during the action of a force in the opposite direction.

FIGS. 4-6 show another embodiment of a toe iron according to the invention. The toe iron comprises a baseplate 30, which is adapted to be secured to the ski by means which are not shown because they are not significant for the invention, e.g., by screws. The baseplate 30 carries two vertical pins 31 and 32, which constitute pivots of a four-bar linkage. The four-bar linkage comprises two-armed levers 33 and 34, each of which has a slot 35 or 36 receiving the pin 31 or 32. Thecoupling member of the four-bar mechanism consists of a channel-shaped sheet metal stamping 37. Two pivot pins 38, 39 extend between the legs of the stamping 37 and pivotally connect the coupling member 37 i serves also as a soleholder member and carries the soleholder proper 40, which is secured by screws 41.

When the lever arms are shown in the position shown in FIGS. 4 and 5, the free arms of the levers33 and 34 of the four-bar. mechanism bear by means of freely rotatable backing rollers '42 and 43 on an abutment block 45, which constitutes a unit-with the baseplate 44. The pins 31, 32 engage those ends of the slots 35 and 36 which are nearer to the backing rollers 42, 43. The abutment block 45 is formed with two concave abutting surfaces 46 and 47, which are formed in accordance with an arc of a circle and engageable by the backing rollers 42, 43. The centers of curvature of the surfaces 46 and 47 coincide with the axes of the pins 31, 32 which are rigid with the baseplate. The abutment block 45 is provided with another arcuate recess 48 between the abutting surfaces 46 and 47.

In addition to the lever 33 or 34, each of the pivot pin 38, 39 of the soleholder member 37 mounts a connecting lever 49 or 50, which is capable of a limited pivotal movement relative to the associated lever 33 or 34. A rotation of the connecting levers 49, 50 from the normal position to one side is provided by'a nose which is formed on the connecting lever and'adapted to engage a wall of a recess in the associated lever 33 or 34. That recess partly receives the connecting lever. The free ends of the connecting levers 49, 50 extend close to the longitudinal center line of the toe iron and each of said free ends is provided with an extension 51 forrnedwith a knife edge. In the normal position of the toe iron shown in FIG. 1, each knife edge is positively held in a vertical notch. These notches are formed in an end face of a pin 52, which has a collar 53 forming an abutment for a preferably prestressed helical compression spring 54. The other end of said spring bears on a bent-up lug 55 of the upper leg of the channel-shaped soleholder member 37. That upper leg constitutes a cover cap. A guide sleeve 56 is secured to the lug 55 and has an outside surface which guides the spring. The pin 52 is axially slidable in the sleeve 56. The central portion of the upper leg of the soleholder member is partly punched so that the spring mechanism may be disposed on a relatively low level. I

As in the preceding embodiment of the invention,

compression spring, and the four-bar linkage can be moved out of that normal position only against the force of the spring. If the skiing boot exerts on the soleholder 40 a force in a direction which is transverse to the longitudinal direction of the ski, e.g., a force directed to the right in FIGS. 4-6, and said force exceeds the initial stress of the spring 54, the levers 33, 34 will rotate about the pins 31 and 32 and the backing rollers 42 and 43 will roll on the abutting surfaces 46 and 47 and prevent the levers 33, 34 from performing a translatory movement owing to the slots 35, 36 in these levers. At this time, the soleholder 40 moves also on an arc of a circle which has a center of curvature that coincides at least approximately with the axis of rotation of the skiing boot on the ski. During that movement of the four-bar linkage, the knife edge 51 of the connecting lever 49 acts on the pin 52 to compress the spring 54. Upon a decrease of the acting force, the compressive force of the spring 54 will return the fourbar linkage to its initial position.

On the other hand, if the soleholder 40 is subjected to a force which exceeds the force required for a release of the toe iron, the four-bar linkage will initially move to its limiting position shown in FIG. 5, as has just been described. In that limiting position, the backing roller 43 is about to disengage the abutting surface 47. Upon a continued movement of the soleholder 40, the backing roller 43 disengages its abutting surface and the slot 36 now permits of a displacement of the lever 34 on the pin 32 until the latter engages the other end of the slot. At this time, the four-bar linkage always collapses under no effort, the soleholder 40 performs a pivotal movement to its open position, and the skiing boot is suddenly released. When the skiing boot has been released, the four-bar linkage can be moved back to its normal position by hand without a considerable effort.

If the soleholder 40 is subjected to a force acting in a direction which is opposite to the one just described, i.e., a force directed to the left in FIGS. 4-6, the fourbar linkage will perform corresponding movements to the other side, with the exception that the helical compression spring 54 is now stressed by the connecting lever 50.

What is claimed is:

1. A toe iron for safety ski bindings, which toe iron comprises: a four-bar linkage and a soleholder constituting a coupling member for said linkage, a baseplate, a pair of levers forming a portion of said linkage and movably mounted with respect to said baseplate, and a spring operatively connected between said coupling member and a predetemiined portion of said linkage to hold said linkage in a predetermined normal position, characterized in that the baseplate (13) includes fixed abutments (l2) symmetrically positioned on either side of a longitudinal center line of said baseplate, and said levers (6,7) each having one end pivotally connected to said coupling member, each of said fixed abutments having a recess and a concave abutting surface (15,16), each said surface adjoining a respective one of said recesses (26) positioned inwardly thereof, at least one freely rotatable backing roller (8,9) provided at the other end of each said lever and abuttingly engaging said concave surface in said normal position and one of said rollers after a predetermined amount of lateral movement of said soleholder against said spring force moving from one said concave surface into said adjoining recess which is located in the direction of said movement whereby said soleholder can pivot into its releasing position with substantially less resistance.

2. A toe iron according to claim 1, further including axles (10) of the backing rollers, said axles acting as pivots of the four-bar linkage.

3. A toe iron according to claim 1, characterized in that that surface of the recess (26) which adjoins the abutting surface (15,16) includes a guideway (26) for th 'd other end of th lever 6 r7 :fi A toe iron according to :lai m characterized in that the spring is disposed between two relatively movable parts of the four-bar linkage.

5. A toe iron according to claim 4, further including connecting levers (21,22) pivotally mounted with respect to the soleholder and wherein the spring (25) acts at one end on the soleholder (U2) and acts at the other end by means of said connecting levers (21,22) on the levers 6,7) of the four-bar linkage. 

1. A toe iron for safety ski bindings, which toe iron comprises: a four-bar linkage and a soleholder constituting a coupling member for said linkage, a baseplate, a pair of levers forming a portion of said linkage and movably mounted with respect to said baseplate, and a spring operatively connected between said coupling member and a predetermined portion of said linkage to hold said linkage in a predetermined normal position, characterized in that the baseplate (13) includes fixed abutments (12) symmetrically positioned on either side of a longitudinal center line of said baseplate, and said levers (6,7) each having one end pivotally connected to said coupling member, each of said fixed abutments having a recess and a concave abutting surface (15,16), each said surface adjoining a respective one of said recesses (26) positioned inwardly thereof, at least one freely rotatable backing roller (8,9) provided at the other end of each said lever and abuttingly engaging said concave surface in said normal position and one of said rollers after a predetermined amount of lateral movement of said soleholder against said spring force moving from one said concave surface into said adjoining recess which is located in the direction of said movement whereby said soleholder can pivot into its releasing position with substantially less resistance.
 2. A toe iron according to claim 1, further including axles (10) of the backing rollers, said axles acting as pivots of the four-bar linkage.
 3. A toe iron according to claim 1, characterized in that that surface of the recess (26) which adjoins the abutting surface (15,16) includes a guideway (26) for the said other end of the lever (6 or 7).
 4. A toe iron according to claim 1, characterized in that the spring is disposed between two relatively movable parts of the four-bar linkage.
 5. A toe iron according to claim 4, further including connecting levers (21,22) pivotally mounted with respect to the soleholder and wherein the spring (25) acts at one end on the soleholder (1/2) and acts at the other end by means of said connecting levers (21,22) on the levers (6,7) of the four-bar linkage. 